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155 HB‐GAM (heparin‐binding growth associated molecule) and n‐syndecan play a role in the formation of thalamocortical connections ?
Author(s) -
Kinnunen A.,
Niemi M.,
Nolo R.,
Kinnunen T.,
Kaksonen M.,
Rauvala H.
Publication year - 1996
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/0736-5748(96)80344-3
Subject(s) - citation , syndecan 1 , associate editor , library science , cognitive science , psychology , computer science , biology , genetics , cell
ECM-molecules such as laminin, tenascin, chondroitin sulphate proteoglycans (CSPG) and heparan sulphate proteoglycans (HSPG) have been suggested to have “signpost” and directing roles in the formation of axonal projections and in the cortical development. We have discovered that the distribution of HB-GAM, an 18 kD neurite-outgrowth promoting protein, in the developing rat brain is spatio-temporally associated with the developing thalamicortical pathways. Using in situ hybridization, thalamic neurons were shown to express N-syndecan mRNA, a HSPG shown to act as a receptor for HB-GAM. Thalamic El6 neurons showed repeatedly a typical growth pattern resembling the HB-GAM distribution when cultured on living brain slice preparation. In virro thalamic neurons expressed more neurite outgrowth on HB-GAM than on laminincoated matrixes. We also tested the effect of soluble heparin on the neurite outgrowth of El6 thalamic neurons in vitro on living sliceculture preparation and the effect of soluble heparin, N-syndecan, HB-GAM and chondroitin sulphate on culture wells coated with HB-GAM, laminin and poly-L-lysine. Neurite outgrowth of thalamic neurons was partially perturbed by soluble heparin on living brain slices and clearly dimished by soluble HB-GAM, Nsyndecan and heparin on HB-GAM coated wells. Our results suggest that HB-GAM may function as an ECM bound cue for thalamic neurons that possess N-syndecan on their cell membrane.